Recently a great deal of concern has been expressed over the accidental or inadvertent contact with sharp pointed cannula used in syringes, catheters and the like causing the spread of various diseases. In addition to hepatitis, acquired immune deficiency syndrome has led to the design of disposable syringes having retractable cannulas or other protective means to prevent the inadvertent piercing of the skin of a third party after an injection or the removal of a catheter. For example, see U.S. Pat. Nos. 4,692,156, 4,804,370, 4813,936 and 4,931,040 which are illustrative of such protective syringes.
Although most of these devices provide means for safely protecting the ends of the needles, the cost of the syringe is relatively high. Moreover, many of these devices are useful only with syringes and do not afford any protection means for cannula used in other devices such as in cathertization and the like. Accordingly, it is an object of the present invention to provide a novel means for protecting such cannula from accidental contact with a user. It is another object of the invention to provide protective means for cannula which are both effective and relatively inexpensive to produce.